Abstract

Since the appearance of our report (Science, 1945, 102, 591), articles written by Graffi (Z. Krebsf., 1939, 49, 477; 1940, 50, 196, 501). came to our attention. In these articles Graffi developed a theory on the derivation of viruses from mitochondria (cf. Graffi s extensive and valuable literature review) and the possible role of mutated mitochondria in the causation of neoplastic diseases, which is almost identical with the views expressed by us. Graffi developed these theories on the basis of a study in which he demonstrated that certain fluorescent carcinogens, as benzopyrene, are absorbed specifically on the mitochondria of animal cells. We came to the same theoretical conclusions as Graffi but from an entirely different approach, in that, in our studies, we were able to show that in plants modified mitochondria (plastids) induce diseases that are fundamentally like those induced by plant viruses. Also, on the basis of chemical and physiological observations, we were led to the concept that certain viruses have evolved from mitochondria or their constituents, implying that similarly modified mitochondria of animal origin can reasonably be expected to be disease causing and that these diseases might be represented by the neoplastic diseases. It is interesting to note that two entirely independent groups of research workers arrived at identical concepts although starting from different points. We regret that our oversight has prevented us from giving due credit to the considerations of Graffi, who terminates his article with the following sentence, which we translate:

"May it however once more especially be emphasized that at the present these trains of thought are still purely speculative and that they have already partially been expressed by other authors in one way or another. However, it might pay to follow them experimentally in one ease or another."